Ultra-wideband wireless communication has great promise in that high data rates may be achieved using a relatively low power transmitter. Ultra-wideband wireless communication may also be denoted as impulse radio because of its use of very short pulses (approximately 1 nanosecond or less). By varying individual pulse positions within a waveform of such pulses, high-data-rate information may be transmitted using very low average power such as in the milliwatt range.
Much interest has been generated for impulse radio because of its low power consumption, extremely high data rate, and excellent multipath immunity. By integrating impulse radio with beamforming capabilities, very low probability of detection performance may be achieved. In contrast to mechanically steered antennas, electronically-controlled beamforming systems are lighter, more agile, and more reliable. A key element of beamforming systems is the design of the phase shifter, which is conventionally implemented using a monolithic microwave integrated circuit (MMIC). However, MMICs are costly and introduce a relatively high insertion loss. As a result, Micro-Electro-Mechanical-Systems (MEMS)-based phase shifters have been developed. But MEMS-based phase shifters are not compatible with conventional semiconductor processes. Moreover, regardless of whether beamforming is provided, the generation of impulses has proven to be extremely difficult to master.
U.S. application Ser. No. 11/555,210 discloses an advantageous pulse generation architecture that can achieve pulse widths of just tens of picoseconds or smaller. By transmitting such pulses in a high-gain directed beam, the range and signal-to-noise limitations of ultra wideband communication are reduced. However, the necessary control signals such as the beamforming commands as well as the data-to-be-transmitted need to be supplied to the pulse generator/modulator.
Accordingly, there is a need in the art for improved control of pulse-position-modulated ultra wideband radio communications.